The present invention relates to labels and labeling, and more particularly to in-mold labels and labeling.
In-mold labels and labeling are well known. Such labels are adhered to an article, such as a bottle, during the molding of the article. The label is placed within the cavity of a mold prior to molding, and the label adheres to the surface of the article during molding.
A typical application is in the production of blow-molded containers. A preprinted label with heat activated adhesive is placed against the inner surface of the mold cavity and held by vacuum ports in the mold. The mold is closed, and the plastic blank is heated and inflated within the mold. The hot plastic presses against the label, activating the adhesive and causing the label to be adhered to the outer surface of the newly molded container. The mold is opened and the labeled container is ejected from the mold. In-mold labels may be furnished as a stack of precut discrete labels or as a continuous web of adjacent labels joined edge to edge and subsequently cut and applied as disclosed in U.S. Pat. No. 5,344,305 to McKillip, incorporated by reference here.
Separate from in-mold labels and labeling, expanded contact labels (ECLs) are known. An ECL includes a booklet or leaflet, which includes information such as instructions, product warnings, or ingredients. The ECL is secured either directly to an article or to a base label that is in turn secured to the article. An ECL typically includes a pressure-sensitive adhesive for adhering the ECL to the article. Usually, an overlaminate is included over the booklet/leaflet to prevent inadvertent separation of the booklet/leaflet from the base label. ECLs are applied to molded articles after molding.
ECL""s may be made from many materials including paper and thermoplastics. ECL""s fabricated of thermoplastics are not as well suited to in-mold use as paper because of the elevated temperatures. The multiple layers of the plastic ECL are subject to different heat intensities as an article is blow molded. Specifically, the layer nearest the molded article is subjected to higher levels of heat than the layer adjacent the mold. This causes the ECL to buckle, and can even cause the layer to delaminate, rendering the label commercially and aesthetically unacceptable.
The aforementioned problems are overcome in the present invention comprising an expanded content label suitable for in-mold use. More specifically, the ECL includes a heat sensitive adhesive to enable application of the ECL in an in-mold process.
The present invention enables an ECL to be applied to an article during molding. The invention eliminates the need to apply an ECL to an article after molding. Accordingly, the manufacture of molded containers having expanded content labels is expedited with the resulting benefit of lower cost.
A second aspect of the invention is directed to a method of applying the novel expanded content label to articles during the molding of the articles. The method includes the steps of (1) placing an ECL having a heat-activated adhesive within a mold, (2) molding an article in the mold thereby activating the adhesive to adhere the ECL to the molded article, and (3) removing the labeled article from the mold.
In a third aspect of the invention, the ECL includes a protective overlaminate. The space between the base layer and the overlaminatexe2x80x94in which the booklet is enclosedxe2x80x94is substantially free of air to prevent air from expanding during the in-mold labeling process and consequently deforming or buckling the ECL.
In a fourth embodiment of the invention, the ECL includes a base label and an overlaminate that deform at different rates, so that together within the moldxe2x80x94where they are subjected to different temperaturesxe2x80x94they deform at a uniform rate. For example, the base layer may be constructed from a thermoplastic that deforms due to heat at a rate faster than that at which the overlaminate material deforms. In this manner, the rates of deformation of the base layer and the overlaminate material are synchronized according to the levels of heat to which they are subjected. Accordingly, the ECL can be used in an in-mold process without unacceptable deformation of the ECL.